Choroid Plexus as a Target in Metal-Induced Neurotoxicity

脉络丛作为金属诱导神经毒性的靶点

• 批准号: 7417332
• 负责人: WEI ZHENG
• 金额: $ 7.69万
• 依托单位: PURDUE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-03-01 至 2009-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7417332
• 关键词: 3' Untranslated Regions; Affect; Area; Binding; Biological Assay; Biological Markers; Blood; Blood - brain barrier anatomy; Blood capillaries; Body Fluids; Brain; Carrier Proteins; Cell Line; Cell membrane; Cells; Cerebrospinal Fluid; Chronic; Condition; Confocal Microscopy; Disease; Electrophoretic Mobility Shift Assay; Epithelial; Epithelium; Exposure to; Ferritin; Functional disorder; Funding; Gene Expression; Gene Silencing; Genetic Transcription; Goals; Grant; Heterogeneous Nuclear RNA; Homeostasis; Human; In Vitro; Iron; Iron Regulatory Protein 1; Iron-Regulatory Proteins; Kinetics; Laboratory Research; Localized; Location; Manganese; Messenger RNA; Metabolic Diseases; Metals; Modeling; Molecular; Neurodegenerative Disorders; Neurons; Nuclear; Parkinson Disease; Parkinsonian Disorders; Peer Review; Perfusion; Polymerase Chain Reaction; Population; Progress Reports; Proteins; RNA; Rate; Rattus; Regulation; Reporting; Research; Research Personnel; Research Support; Reverse Transcriptase Polymerase Chain Reaction; Role; Rotenone; Running; SLC11A2 gene; Score; Serum; Side; Small Interfering RNA; Steel; Structure; Structure of choroid plexus; Study Section; System; Techniques; Testing; Time; Transferrin Receptor; US Army Medical Research and Material Command; Welding; Western Blotting; base; blood cerebrospinal fluid barrier; capillary; career; divalent metal; early onset; in vivo; insight; knock-down; mRNA Transcript Degradation; metal transporting protein 1; neurotoxicity; novel; programs; research study; stem; toxicant; uptake

DESCRIPTION (provided by applicant): Altered brain iron (Fe) homeostasis has been shown in idiopathic Parkinson's disease (IPD) and in manganese (Mn)-induced Parkinsonism. The current proposal continues the central theme of our long-time research goal, i.e., to explore the role of brain barrier systems in metal-induced neurotoxicities. Divalent metal transporter-1 (DMT1) and metal transport protein-1 (MTP1) are two newly discovered metal transporters and function to transport metals across the cell membrane. In the Progress Report, we have demonstrated the presence of DMT1 and MTP1 in the choroid plexus, where the blood-cerebrospinal fluid (CSF) barrier (BCB) is located. We have also observed that Mn exposure increases DMT1 expression and mobilizes subcellular MTP1 in the BCB epithelia. However, the questions as to where the DMT1 and MTP1 are subcellularly co-localized in the BCB, how they function in concert to respond to divalent-metal fluxes on both sides of the BCB, by what mechanism Mn exposure alters the expression and function of both transporters, and how the dysregulation of DMT1 and MTP1 in the BCB by Mn exposure affects brain homeostasis of Fe and Mn, remain mysterious. Thus, to understand the structural functionality of DMT1 and MTP1 in the brain barrier and their dysfunction-associated neuronal disorders, we hypothesize that the altered expression of DMT1 and MTP1 in the choroid plexus following Mn exposure contributes to Mn- induced Fe metabolism disorder in the CSF. Our specific aims are: (1) to explore whether DMT1 and MTP1 control the direction of Fe transport at the BCB by investigating the subcellular location of DMT1 and MTP1 in choroidal epithelia, by blocking or inducing DMT1 and MTP1 expression to determine the direction of Fe and Mn transport at BCB, and by using siRNA technique to silence the genes encoding DMT1 and MTP1 to investigate Fe and Mn uptake and transport kinetics under DMT1 or MTP1 knock-down conditions; (2) to explore whether in vivo chronic Mn exposure distorts the expression of DMT1 and MTP1 in the BCB and selected regional blood-brain barrier and leads to increased fluxes of Fe between the blood and CSF, by using a rat chronic Mn exposure model and by a ventriculo-cisternal perfusion technique; and (3) to explore whether Mn exposure interferes the binding of iron-regulatory proteins to mRNAs of DMT1 and MTP1, since the stem-loop structure exists in 3'-untranslated regions (UTR) and 5'-UTR in DMT1 and MTP1 mRNA, respectively. Studies proposed in this application will define the inter-relationship between DMT1 and MTP1 in the BCB with regard to their subcellular locations, roles in transport of divalent metals at the BCB, and their regulation as affected by Mn exposure; will provide insight into the molecular mechanism by which Mn affects divalent Fe transport by brain barriers; and will ultimately provide a better understanding of Fe dysfunction-related neuronal diseases such as IPD.

描述（由申请人提供）：在特发性帕金森病（IPD）和锰（Mn）诱导的帕金森综合征中显示了脑铁（Fe）稳态的改变。目前的建议继续我们长期研究目标的中心主题，即，探讨脑屏障系统在金属诱导的神经毒性中的作用。二价金属转运蛋白1（DMT 1）和金属转运蛋白1（MTP 1）是近年来发现的两种金属转运蛋白，其功能是跨细胞膜转运金属。在进展报告中，我们已经证明了DMT 1和MTP 1存在于脉络丛中，血-脑脊液（CSF）屏障（BCB）位于脉络丛中。我们还观察到，锰暴露增加DMT 1的表达和动员亚细胞MTP 1在BCB上皮细胞。然而，问题的DMT 1和MTP 1是亚细胞共定位在BCB，他们如何在音乐会上响应二价金属通量两侧的BCB，通过什么机制锰暴露改变这两种转运蛋白的表达和功能，以及如何失调的DMT 1和MTP 1在BCB锰暴露影响脑内稳态的铁和锰，仍然是神秘的。因此，为了理解DMT 1和MTP 1在脑屏障中的结构功能及其功能障碍相关的神经元疾病，我们假设Mn暴露后脉络丛中DMT 1和MTP 1的表达改变有助于Mn诱导的CSF中的Fe代谢障碍。我们的具体目标是：（1）通过研究DMT 1和MTP 1在脉络膜上皮细胞中的亚细胞定位，通过阻断或诱导DMT 1和MTP 1的表达来确定BCB铁和锰转运的方向，利用siRNA技术沉默DMT 1和MTP 1基因，研究DMT 1和MTP 1基因敲低条件下铁、锰的吸收和转运动力学;（2）采用大鼠慢性染锰模型和脑室-脑池灌流技术，探讨在体慢性染锰是否改变了BCB和特定区域血脑屏障中DMT 1和MTP 1的表达，并导致血液与CSF之间的铁通量增加;以及（3）探索Mn暴露是否干扰铁调节蛋白与DMT 1和MTP 1的mRNA的结合，因为茎环结构分别存在于DMT 1和MTP 1 mRNA的3 '-非翻译区（UTR）和5'-非翻译区（UTR）。本申请中提出的研究将确定BCB中DMT 1和MTP 1之间的相互关系，包括它们的亚细胞位置、在BCB中二价金属转运中的作用以及它们受Mn暴露影响的调节;将深入了解Mn通过脑屏障影响二价Fe转运的分子机制;并将最终提供对Fe功能障碍相关的神经元疾病如IPD的更好理解。